Routine clinical application of implantable prosthetic fluid energy transfer devices requires reliable operation of a system comprised of pumping, storage, flow channel, and valving mechanisms. Inconsistent clinical results have been obtained as a result of: (1) material fatigue leading to component failure, (2) deterioration in valve crack and reseat characteristics which alter ability to repeatedly obtain and sustain system operating states, (3) improper design or selection of system components which prevents reproducibility of operating characteristics due to component performance variances under dynamic system conditions, and (4) improper selection of patients has complicated device application, a design study of the constituent system components and a determination of how this characterization can lead to predictive system performance is herein described. The development of quantitative methods to aid in patient selection and in device performance evaluation will further delineate a rationale for prosthetic device applications.